of Growing Timber Trees, 36*7 



Whatever the lengths of the boles of trees increasing as 

 above may be, their increase is five per cent, per annum, one 

 year after their girt in the middle is 15 inches, but not longer. 



Again, let it be supposed that trees sixty years of age 

 have increased annually, during their growth, eighteen 

 inches in height, and two inches in circumference, the girt 

 and contents of their boles, if of the under-mentioned 

 lengths, will be as under, viz. 



Contents. 



Ft. In. pt. 



Trees with 24 feet boles, will be 26 inches girt at 12 feet high, 1 12 8 O 



Do. SO do. 25 do. 15 do. 130 2 6 ' 



Do. 36 do. 24 do. J 8 do. 144 O 



Do. 48 do. 22 do. 24 do. 161 4 



Do. 60 do. 20 do. 80 do. 166 8 



Here again we may suppose that the forty- eight fret bole, 

 by swelling faster than the sixty feet bole, may exceed it in 

 measure at sixty years of age, and this it would do, were 

 the girt increased only half an inch. And if the thirty-six 

 feet bole was increased two inches in girt, it would exceed 

 both the forty- eight and sixty feet boles. But trees of such 

 swift growth are frequently cut down before they are sixty 

 years old. At forty years of age the thirty-six feet bole, if 

 it swell no faster than the forty-eight feet bole, will contain 

 more timber if measured according to the present erroneous 

 method. (The greater disproportion there is between the 

 two ends of a piece of timber, and the more disadvanta- 

 geously it measures, when the girt is taken in the middle.) 

 I suppose that in timber of this swift growth, the longer 

 boles are frequently not worth more per foot than the shorter 

 boles; therefore, in this case, that length of bole should be. 

 fixed on which is likely to measure most at the period when, 

 the trees are intended to be felled. 



Whatever the lengths of the boles of trees increasing as 

 above may be, their increase is five per cent, per annum, one 

 year after their girt in the middle is 20 inches, but not longer. 



It appears from the last observations and calculation?, 

 that the annual increase in the boles of trees by their growth, 

 ceases to be equal to five per cent, pet annum some time 



between 



